year 12 biology summer work 2020 dear biologist, current ... · year 12 biology summer work 2020...
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Year 12 Biology Summer Work 2020
Dear Biologist,
Having studied Biology for the last two or three years it must be frustrating for some of you to not
have had the opportunity to sit your GCSE this year. Your preparations for the GCSE will not have been
in vain as you will see that GCSE Biology leads on nicely to A level Biology. Below is a brief outline of
the topics covered in your first and second years. Task 1 of your summer work tests you on your
current knowledge and helps to identify which areas we may need to spend more time on when we
get to the relevant topic.
Assessment PAGS / Practical
2.1.1 Cell structure Light microscopes and graticules PAG 1.2 Light microscope red blood cells
2.1.2 Biological
molecules
PAG 9.1 Qualitative protein PAG 9.2 Qualitative lipids PAG 9.3 Qualitative glucose PAG 5.2 Determining glucose concentration (calibration curve)
2.1.3 Nucleotides and
nucleic acids
PAG 10.1 DNA and RASmol
2.1.4 Enzymes
PAG 4.1 Enzymes and substrate conc. PAG 4.2 Enzymes conc. PAG 4.3 Temperature and amylase
2.1.5 Biological
membranes
PAG 5.1 Temperature and membranes PAG 8.1 Water potential and potato PAG 8.2 Osmosis in artificial cell PAG 8.3 Rate of diffusion through a membrane
2.1.6 Cell division
PAG 1.1 Light microscope to look at mitosis in root tip Prepared slides for drawing and measurement Rat dissection
3.1.1 Exchange
surfaces
PAG 1.3 Light microscope to look at lung tissue Spirometer traces Observation of living locusts
3.1.2 Transport in
Animals
PAG 2.1 Dissection of heart PAG 11.2 Heart rate of daphnia? PAG 11.1 Effect of exercise on pulse rate (paired t-test)
3.1.3 Transport in
plants
PAG 2.2 Dissection of a stem (2 x double) PAG 5.3 Potometer (2 x double)
4.1.1 Communicable
diseases
PAG 7.1 effects of antibiotics
4.2.1 Biodiversity
3.1 Species diversity 3.2 Distribution and abundance (FIELD STUDIES DAY + 2 doubles) 3.3 Correlation between spp and factor (FIELD STUDIES DAY) – Spearmans rank
4.2.2 Classification
and evolution
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Year 12 Biology Summer Work 2020
Assessment PAGS / Practical
5.1.1 Communication
and Homeostasis
5.1.2 Excretion
Kidney dissection/ kidney slides (graticules used to measure glomerulus) PAG2/PAG1 Mock urine (revisit bio molecules tests) Liver slides
5.1.3. Neuronal
communication
Include muscle etc from 5.1.5 PAG 2.3 Chicken wing dissection
5.1.4 Hormonal
communication
Pancreas microscopy (prepared slides) – measuring islets of langerhan PAG 11 Effect of adrenalin on pulse rate (paired t-test)
5.1.5 Plant and
animal responses
PAG 11.3 Phototropism coleoptile
5.2.1 Photosynthesis
PAG 12.3 Research photosynthesis PAG 6.3 Photosynthetic pigments chromatography DCPIP demo
5.2.2 Respiration PAG 12.1 Research respiration Respirometers
6.1.1 Cellular control
6.1.2 Patterns of
inheritance
PAG 12.2 Fruit flies genetic crosses
6.1.3 Manipulating
genomes
6.2.1 Cloning and
biotechnology
Sanger sequencing kit PAG 7.2 Dilution plating population density PAG 7.3 GFP bacterial transformation (Portsmouth Uni?) Immobilised lactose PAG 10.3 pH change during yoghurt production
6.3.1 Ecosystems
6.3.2 Populations and
sustainability
As you can see in the table above we spend a lot of lessons helping you to gain practical skills in
preparation for further studies at university or for future careers.
Ten percent of the A level also assesses your mathematical ability and this sometime surprises
students choosing A level Biology. Task 2 gives you an idea of the type of questions that you will be
covering at A level. It helps us to identify how confident you are when handling data.
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Year 12 Biology Summer Work 2020
Included in your summer work are two main tasks.
Task 1 – multiple choice quiz testing your knowledge on the content taught at
GCSE.
This is mainly to assess which areas of the course we may be able to cover fairly quickly and which
areas we may have to spend a little longer on. The quiz will take approximately 1 hour and is 42
questions long, you will need a calculator for some of the questions.
You may use the multiple choice quiz sent with this document and record your answers with an (x) in
the appropriate box on the separate answer sheet. Should you do this you will need to print off and
bring the completed answer sheets to the first lesson of the year.
or
log on to socrative (https://b.socrative.com/login/student/) and enter room white8738. Please
record your name by surname and then first letter of your first name. On socrative you will get instant
feedback. This may help you identify which areas of the GCSE you might want to spend extra time
going over before starting the A level course.
Task 2 – short answer questions testing your mathematical skills.
Please use the maths sheet provided which gives some guidance on how to attempt the questions.
Complete the answers on the separate answer sheet.
Please do not hesitate to email me any questions should you get stuck! We look forward to hopefully
seeing you in September.
Mrs White
https://b.socrative.com/login/student/
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Year 12 Biology Summer Work Question Sheet
You are not expected to write your answers on this sheet but on the answer grid.
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GCSE → A Level transition
Student sheet
OCR A Biology
© Oxford University Press 2019 http://www.oxfordsecondary.co.uk/acknowledgements
This resource sheet may have been changed from the original 1
Transition from GCSE to A Level
Moving from GCSE Science to A Level can be a daunting leap. You’ll be expected to remember a lot more facts, equations, and definitions, and you will need to learn new maths skills and develop confidence in applying what you already know to unfamiliar situations.
This worksheet aims to give you a head start by helping you:
to pre-learn some useful knowledge from the first chapters of your A Level course
understand and practice of some of the maths skills you’ll need.
Learning objectives
After completing the worksheet you should be able to:
define practical science key terms
recall the answers to the retrieval questions
perform maths skills including:
o converting between units, standard form, and prefixes
o using significant figures
o rearranging formulae
o magnification calculations
o calculating percentages, errors, and uncertainties
o drawing and interpreting line graphs.
http://www.oxfordsecondary.co.uk/acknowledgements
-
GCSE → A Level transition
Student sheet
OCR A Biology
© Oxford University Press 2019 http://www.oxfordsecondary.co.uk/acknowledgements
This resource sheet may have been changed from the original 2
Retrieval questions
You need to be confident about the definitions of terms that describe measurements and results in A Level Biology.
Learn the answers to the questions below, then cover the answers column with a piece of paper and write as many answers as you can. Check and repeat.
Practical science key terms
When is a measurement valid? when it measures what it is supposed to be measuring
When is a result accurate? when it is close to the true value
What are precise results? when repeat measurements are consistent/agree closely with each
other
What is repeatability? how precise repeated measurements are when they are taken by the
same person, using the same equipment, under the same conditions
What is reproducibility? how precise repeated measurements are when they are taken by
different people, using different equipment
What is the uncertainty of a measurement? the interval within which the true value is expected to lie
Define measurement error the difference between a measured value and the true value
What type of error is caused by results varying
around the true value in an unpredictable way?
random error
What is a systematic error? a consistent difference between the measured values and true
values
What does zero error mean? a measuring instrument gives a false reading when the true value
should be zero
Which variable is changed or selected by the
investigator?
independent variable
What is a dependent variable? a variable that is measured every time the independent variable is
changed
Define a fair test a test in which only the independent variable is allowed to affect the
dependent variable
What are control variables? variables that should be kept constant to avoid them affecting the
dependent variable
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-
GCSE → A Level transition
Student sheet
OCR A Biology
© Oxford University Press 2019 http://www.oxfordsecondary.co.uk/acknowledgements
This resource sheet may have been changed from the original 3
Basic components of living systems
Learn the answers to the questions below then cover the answers column with a piece of paper and write as many answers as you can. Check and repeat.
What is the formula to calculate magnification?
Why are cells stained before being viewed with a light
microscope?
staining increases contrast between different cell components,
makes them visible, and allows them to be identified
What is an eyepiece graticule? a glass disc that fits on top of the eyepiece lens that is marked
with a fine scale from 1 to 100
What is a stage micrometer? a microscope slide with a very accurate scale in micrometers (µ)
engraved on it
What is a scientific drawing? a labelled line drawing that is used to highlight particular features
and does not include unnecessary detail or shading, it should
always have a title and state the magnification
What is magnification? how many times larger an image is than the actual size of the
object being viewed
What is resolution? the ability to see individual objects as separate entities
What is the function of the nucleus? controls the metabolic activities of the cell as it contains genetic
information in the form of DNA
What is the nucleolus? area within the nucleus that is responsible for producing
ribosomes
What is the function of mitochondria? site of production of ATP in the final stages of cellular respiration
What are vesicles? membranous sacs that are used to transport materials in the cell
What are lysosomes? specialised forms of vesicles with hydrolytic enzymes that break
down waste material in cells
What is the role of the cytoskeleton? controls cell movement, movement of organelles within the cell,
and provides mechanical strength to the cell
Name the three types of cytoskeletal filaments microfilaments, microtubules, and intermediate fibres
Give two types of extension that protrude from some
cells
flagella (whip-like protrusions) and cilia (tail-like protrusions)
What is the endoplasmic reticulum (ER)? a network of membranes enclosing flattened sacs called
cisternae
What are the functions of the two types of ER? smooth ER – lipid and carbohydrate synthesis, and storage
rough ER – synthesis and transport of proteins
http://www.oxfordsecondary.co.uk/acknowledgements
-
GCSE → A Level transition
Student sheet
OCR A Biology
© Oxford University Press 2019 http://www.oxfordsecondary.co.uk/acknowledgements
This resource sheet may have been changed from the original 4
What is the function of the Golgi apparatus? plays a part in modifying proteins and packaging them into
vesicles
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GCSE → A Level transition
Student sheet
OCR A Biology
© Oxford University Press 2019 http://www.oxfordsecondary.co.uk/acknowledgements
This resource sheet may have been changed from the original 5
Maths skills
1 Numbers and units
1.1 Units and prefixes
A key criterion for success in biological maths lies in the use of correct units and the management of numbers. The units scientists use are from the Système Internationale – the SI units. In biology, the most commonly used SI base units are metre (m), kilogram (kg), second (s), and mole (mol). Biologists also use SI derived units, such as square metre (m2), cubic metre (m3), degree Celsius (°C), and litre (l).
To accommodate the huge range of dimensions in our measurements they may be further modified using appropriate prefixes. For example, one thousandth of a second is a millisecond (ms). Some of these prefixes are illustrated in the table below.
Multiplication factor Prefix Symbol
109 giga G
106 mega M
103 kilo k
10–2 centi c
10–3 milli m
10–6 micro µ
10–9 nano n
Practice questions
1 A burger contains 4 500 000 J of energy. Write this in:
a kilojoules b megajoules.
2 HIV is a virus with a diameter of between 9.0×10−8 m and 1.20×10−7 m.
Write this range in nanometres.
1.2 Powers and indices
Ten squared = 10 × 10 = 100 and can be written as 102. This is also called ‘ten to the power of 2’.
Ten cubed is ‘ten to the power of three’ and can be written as 103 = 1000.
The power is also called the index.
Fractions have negative indices:
one tenth = 10−1 = 1/10 = 0.1
one hundredth = 10−2 = 1/100 = 0.01
Any number to the power of 0 is equal to 1, for example, 290 = 1.
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GCSE → A Level transition
Student sheet
OCR A Biology
© Oxford University Press 2019 http://www.oxfordsecondary.co.uk/acknowledgements
This resource sheet may have been changed from the original 6
If the index is 1, the value is unchanged, for example, 171 = 17.
When multiplying powers of ten, you must add the indices.
So 100 × 1000 = 100 000 is the same as 102 × 103 = 102 + 3 = 105
When dividing powers of ten, you must subtract the indices.
So 100/1000 = 1/10 = 10−1 is the same as 102/103 = 102 − 3 = 10−1
But you can only do this when the numbers with the indices are the same.
So 102 × 23 = 100 × 8 = 800
And you can’t do this when adding or subtracting.
102 + 103 = 100 + 1000 = 1100
102 − 103 = 100 − 1000 = −900
Remember: You can only add and subtract the indices when you are multiplying or dividing the numbers, not adding or subtracting them.
Practice questions
3 Calculate the following values. Give your answers using indices.
a 108 × 103 b 107 × 102 × 103
c 103 + 103 d 102 − 10−2
4 Calculate the following values. Give your answers with and without using indices.
a 105 ÷ 104 b 103 ÷ 106
c 102 ÷ 10−4 d 1002 ÷ 102
1.3 Converting units
When doing calculations, it is important to express your answer using sensible numbers. For example, an answer of 6230 μm would have been more meaningful expressed as 6.2 mm.
If you convert between units and round numbers properly, it allows quoted measurements to be understood within the scale of the observations.
To convert 488 889 m into km:
A kilo is 103 so you need to divide by this number, or move the decimal point three places to the left.
488 889 ÷ 103 = 488.889 km
However, suppose you are converting from mm to km: you need to go from 103 to 10−3, or move the decimal point six places to the left.
333 mm is 0.000 333 km
Alternatively, if you want to convert from 333 mm to nm, you would have to go from 10−9 to 10−3, or move the decimal point six places to the right.
333 mm is 333 000 000 nm
Practice question
5 Calculate the following conversions:
a 0.004 m into mm b 130 000 ms into s
c 31.3 ml into μl d 104 ng into mg
6 Give the following values in a different unit so they make more sense to the reader.
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GCSE → A Level transition
Student sheet
OCR A Biology
© Oxford University Press 2019 http://www.oxfordsecondary.co.uk/acknowledgements
This resource sheet may have been changed from the original 7
Choose the final units yourself. (Hint: make the final number as close in magnitude to zero as you can. For example, you would convert 1000 m into 1 km.)
a 0.000 057 m b 8 600 000 μl c 68 000 ms d 0.009 cm
2 Decimals, standard form, and significant figures
2.1 Decimal numbers
A decimal number has a decimal point. Each figure before the point is a whole number, and the figures after the point represent fractions.
The number of decimal places is the number of figures after the decimal point. For example, the number 47.38 has 2 decimal places, and 47.380 is the same number to 3 decimal places.
In science, you must write your answer to a sensible number of decimal places.
Practice questions
1. New antibiotics are being tested. A student calculates the area of clear zones in Petri dishes in which the antibiotics have been used. List these in order from smallest to largest.
0.0214 cm2 0.03 cm2 0.0218 cm2 0.034 cm2
2. A student measures the heights of a number of different plants. List these in order from smallest to largest.
22.003 cm 22.25 cm 12.901 cm 12.03 cm 22 cm
2.2 Standard form
Sometimes biologists need to work with numbers that are very small, such as dimensions of organelles, or very large, such as populations of bacteria. In such cases, the use of scientific notation or standard form is very useful, because it allows the numbers to be written easily.
Standard form is expressing numbers in powers of ten, for example, 1.5×107 microorganisms.
Look at this worked example. The number of cells in the human body is approximately 37 200 000 000 000. To write this in standard form, follow these steps:
Step 1: Write down the smallest number between 1 and 10 that can be derived from the number to be converted. In this case it would be 3.72
Step 2: Write the number of times the decimal place will have to shift to expand this to the original number as powers of ten. On paper this can be done by hopping the decimal over each number like this:
until the end of the number is reached.
In this example that requires 13 shifts, so the standard form should be written as 3.72×1013.
For very small numbers the same rules apply, except that the decimal point has to hop backwards. For example, 0.000 000 45 would be written as 4.5×10−7.
Practice questions
3 Change the following values to standard form.
a 3060 kJ b 140 000 kg c 0.000 18 m d 0.000 004 m
4 Give the following numbers in standard form.
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GCSE → A Level transition
Student sheet
OCR A Biology
© Oxford University Press 2019 http://www.oxfordsecondary.co.uk/acknowledgements
This resource sheet may have been changed from the original 8
a 100 b 10 000 c 0.01 d 21 000 000
5 Give the following as decimals.
a 106 b 4.7×109 c 1.2×1012 d 7.96×10−4
2.3 Significant figures
When you use a calculator to work out a numerical answer, you know that this often results in a large number of decimal places and, in most cases, the final few digits are ‘not significant’. It is important to record your data and your answers to calculations to a reasonable number of significant figures. Too many and your answer is claiming an accuracy that it does not have, too few and you are not showing the precision and care required in scientific analysis.
Numbers to 3 significant figures (3 s.f.):
7.88 25.4 741
Bigger and smaller numbers with 3 significant figures:
0.000 147 0.0147 0.245 39 400 96 200 000 (notice that the zeros before the figures and after the figures are not significant – they just show you how large the number is by the position of the decimal point).
Numbers to 3 significant figures where the zeros are significant:
207 4050 1.01 (any zeros between the other significant figures are significant).
Standard form numbers with 3 significant figures:
9.42×10−5 1.56×108
If the value you wanted to write to 3.s.f. was 590, then to show the zero was significant you would have to write:
590 (to 3.s.f.) or 5.90 × 102
Remember: For calculations, use the same number of figures as the data in the question with the lowest number of significant figures. It is not possible for the answer to be more accurate than the data in the question.
Practice question
6 Write the following numbers to i 2 s.f. and ii 3 s.f.
a 7644 g
b 27.54 m
c 4.3333 g
d 5.995×102 cm3
7 The average mass of oxygen produced by an oak tree is 11800 g per year.
Give this mass in standard form and quote your answer to 2 significant figures.
3 Working with formulae
It is often necessary to use a mathematical formula to calculate quantities. You may be tested on your ability to substitute numbers into formulae or to rearrange formulae to find specific values.
3.1 Substituting into formulae
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GCSE → A Level transition
Student sheet
OCR A Biology
© Oxford University Press 2019 http://www.oxfordsecondary.co.uk/acknowledgements
This resource sheet may have been changed from the original 9
Think about the data you are given in the question. Write down the equation and then think about how to get the data to substitute into the equation. Look at this worked example.
A cheek cell has a 0.06 mm diameter. Under a microscope it has a diameter 12 mm. What is the magnification?
magnification = image size (mm) ÷ object size (mm) or M =
Substitute the values and calculate the answer:
M = 12 mm/0.06 mm = 12/0.06 = 200
Answer: magnification = ×200 (magnification has no units)
Sometimes an equation is more complicated and the steps need to be carried out in a certain order to succeed. A general principle applies here, usually known by the mnemonic BIDMAS. This stands for Brackets, Indices (functions such as squaring or powers), Division, Multiplication, Addition, Subtraction.
Practice questions
1. Calculate the magnification of a hair that has a width of 6.6 mm on a photograph. The hair is 165 µm wide.
2 Estimate the area of a leaf by treating it as a triangle with base 2 cm and height 9 cm.
3 Estimate the area of a cell by treating it as a circle with a diameter of 0.7 µm. Give your answer in µm2.
4 An Amoeba population starts with 24 cells. Calculate how many Amoeba cells would be present in the culture after 7 days if each cell divides once every 20 hours. Use the equation Nt = N0 × 2n where Nt = number after time t, N0 = initial population, n = number of divisions in the given time t.
5 In a quadrat sample, an area was found to contain 96 aphids, 4 ladybirds, 22 grasshoppers,
and 3 ground beetles. Calculate the diversity of the site using the equation D = where n = number of each species, N = grand total of all species, and D = diversity.
Remember: In this equation there is a part that needs to be done several times then summed, shown by the symbol Σ.
3.2 Rearranging formulae
Sometimes you will need to rearrange an equation to calculate the answer to a question. For example, the relationship between magnification, image size, and actual size of specimens in
micrographs usually uses the equation M = , where M is magnification, I is size of the image, and O = actual size of the object.
You can use the algebra you have learnt in Maths to rearrange equations, or you can use a triangle like the one shown.
Cover the quantity you want to find. This leaves you with either a fraction or a multiplication:
M = I ÷ O O = I ÷ M I = M × O
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GCSE → A Level transition
Student sheet
OCR A Biology
© Oxford University Press 2019 http://www.oxfordsecondary.co.uk/acknowledgements
This resource sheet may have been changed from the original 10
Practice questions
6. A fat cell is 0.1 mm in diameter. Calculate the size of the diameter seen through a microscope with a magnification of ×50.
7. A Petri dish shows a circular colony of bacteria with a cross-sectional area of 5.3 cm2. Calculate the radius of this area.
8 In a photograph, a red blood cell is 14.5 mm in diameter. The magnification stated on the image is ×2000. Calculate the real diameter of the red blood cell.
9 Rearrange the equation 34 = 2a/135 × 100 and find the value of a.
10 The cardiac output of a patient was found to be 2.5 dm3 min−1 and their heart rate was 77 bpm. Calculate the stroke volume of the patient.
Use the equation: cardiac output = stroke volume × heart rate.
11 In a food chain, efficiency = × 100
A farmer fed 25 kg of grain to his chicken. The chicken gained weight with an efficiency of 0.84. Calculate the weight gained by the chicken.
4 Magnification
To look at small biological specimens you use a microscope to magnify the image that is observed. The microscope was developed in the 17th century. Anton van Leeuwenhoek used a single lens and Robert Hooke used two lenses. The lenses focus light from the specimen onto your retina to produce a magnified virtual image. The magnification at which observations are made depends on the lenses used.
4.1 Calculating the magnifying power of lenses
Lenses each have a magnifying power, defined as the number of times the image is larger than the real object. The magnifying power is written on the lens.
To find the magnification of the virtual image that you are observing, multiply the magnification powers of each lens used. For example, if the eyepiece lens is ×10 and the objective lens is ×40 the total magnification of the virtual image is 10 × 40 = 400.
Practice questions
1. Calculate the magnification of the virtual image produced by the following combinations of lenses:
a objective ×10 and eyepiece ×12 b objective ×40 and eyepiece ×15
4.2 Calculating the magnification of images
Drawings and photographs of biological specimens should always have a magnification factor stated. This indicates how much larger or smaller the image is compared with the real specimen.
The magnification is calculated by comparing the sizes of the image and the real specimen. Look at this worked example.
The image shows a flea which is 1.3 mm long. To calculate the magnification of the image, measure the image (or the scale bar if given) on the paper (in this example, the body length as indicated by the line A–B).
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GCSE → A Level transition
Student sheet
OCR A Biology
© Oxford University Press 2019 http://www.oxfordsecondary.co.uk/acknowledgements
This resource sheet may have been changed from the original 11
For this image, the length of the image is 42 mm and the length of the real specimen is 1.3 mm.
magnification = = 42/1.3 = 32.31
The magnification factor should therefore be written as ×32.31
Remember: Use the same units. A common error is to mix units when performing these calculations. Begin each time by converting measurements to the same units for both the real specimen and the image.
Practice question
2 Calculate the magnification factor of a mitochondrion that is 1.5 µm long.
4.3 Calculating real dimensions
Magnification factors on images can be used to calculate the actual size of features shown on drawings and photographs of biological specimens. For example, in a photomicrograph of a cell, individual features can be measured if the magnification is stated. Look at this worked example.
The magnification factor for the image of the open stoma is ×5000.
This can be used to find out the actual size of any part of the cell, for example, the length of one guard cell, measured from A to B.
Step 1: Measure the length of the guard cell as precisely as possible. In this example the image of the guard cell is 52 mm long.
Step 2: Convert this measurement to units appropriate to the image. In this case you should use µm because it is a cell.
So the magnified image is 52 × 1000 = 52 000 µm
Step 3: Rearrange the magnification equation (see Topic 3.2) to get:
real size = size of image/magnification = 52 000/5000 = 10.4
So the real length of the guard cell is 10.4 µm.
http://www.oxfordsecondary.co.uk/acknowledgements
-
GCSE → A Level transition
Student sheet
OCR A Biology
© Oxford University Press 2019 http://www.oxfordsecondary.co.uk/acknowledgements
This resource sheet may have been changed from the original 12
Practice question
3 Use the magnification factor to determine the actual size of a bacterial cell.
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Year 12 Biology Summer Work Answer Sheet Name:
Task 1 – knowledge test (you may answer this on socrative instead)
Question A B C D
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Task 2 – Maths answer sheet.
1 Numbers and units
Question
1.1 Numbers and units
Answer
1 A burger contains 4 500 000 J of energy. Write this in:
a kilojoules
b megajoules.
a b
2 HIV is a virus with a diameter of between 9.0×10
−8 m and 1.20×10
−7 m.
Write this range in nanometres.
1.2 Powers and indices Answer
3 Calculate the following values. Give your answers using indices.
a108
×103
b107
×102
×103
c103
+103
d102 −10
−2
4 Calculate the following values. Give your answers with and without using indices.
a. 105
÷104
b. 103
÷106
c. 102
÷10−4
d. 1002
÷102
a b c
d
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Question
1.3 Converting units
Answer
5 Calculate the following conversions: a 0.004 m into mm
b 130 000 ms into s
c 31.3 ml into μl
d 104 ng into mg
a b c d
6 Give the following values in a different unit so they make more sense to the reader. Choose the final units yourself. (Hint: make the final number as close in magnitude to zero as you can. For example, you would convert 1000 m into 1 km.) a 0.000 057 m
b 8 600 000 μl
c 68 000 ms
d 0.009 cm
a b c d
2 Decimals, standard form, and significant figures
Question
2.1 Decimal numbers Answer
1 New antibiotics are being tested. A student calculates the area of clear zones in Petri dishes in which the antibiotics have been used. List these in order from smallest to largest.
0.0214 cm2
0.03 cm2
0.0218 cm2
0.034 cm2
2 A student measures the heights of a number of different plants. List these in order from smallest to largest. 22.003 cm 22.25 cm 12.901 cm 12.03 cm 22 cm
2.2 Standard form
3 Change the following values to standard form. a 3060 kJ
b 140 000 kg
c 0.000 18 m
d 0.000 004 m
a b c d
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Question
2.1 Decimal numbers Answer
4 Give the following numbers in standard form. a 100
b 10 000
c 0.01
d 21 000 000
a b c d
5 Give the following as decimals.
a 106
b 4.7×109
c 1.2×1012
d 7.96×10−4
a b c d
Question
2.3 Significant figures
Answer
6 Write the following numbers to i 2 s.f. and ii 3 s.f.
a 7644 g
b 27.54 m
c 4.3333 g
d 5.995×102
cm3
a b c d
7 The average mass of oxygen produced by an oak tree is 11800 g per year.
Give this mass in standard form and quote your answer to 2 significant figures.
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3 Working with formulae
Quest
ion 3.1 substituting into formula Answer
1 Calculate the magnification of a hair that has a width of 6.6 mm on a photograph. The hair is 165 μm wide.
2 Estimate the area of a leaf by treating it as a triangle with base 2 cm and height 9 cm.
3 Estimate the area of a cell by treating it as a circle with a diameter of 0.7 μm. . Give your answer in µm2.
4 An Amoeba population starts with 24 cells. Calculate how many Amoeba cells would be present in the culture after 7 days if each cell divides once every 20
hours. Use the equation Nt = N0 × 2n
where Nt = number after time t, N0 =
initial population, n = number of divisions in the given time t.
5 In a quadrat sample, an area was found to contain 96 aphids, 4 ladybirds, 22 grasshoppers,
and 3 ground beetles. Calculate the diversity of the site using the equation D
=
where n = number of each species, N = grand total of all species, and D = diversity.
3.2 Rearranging formula Answer
6 A fat cell is 0.1 mm in diameter. Calculate the size of the diameter seen through a microscope with a magnification of ×50.
7 A Petri dish shows a circular colony of bacteria with a cross-sectional area of 5.3 cm2 . Calculate the radius of this area.
8 In a photograph, a red blood cell is 14.5 mm in diameter. The magnification stated on the image is ×2000. Calculate the real diameter of the red blood cell.
9 Rearrange the equation 34 = 2a/135 × 100 and find the value of a.
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Quest
ion 3.1 substituting into formula Answer
10 The cardiac output of a patient was found to be 2.5 dm
3 min
−1 and their heart
rate was 77bpm. Calculate the stroke volume of the patient.
Use the equation: cardiac output = stroke volume × heart rate.
11 In a food chain, efficiency =
biomass transferred × 100
biomasstaken in A farmer fed 25 kg of grain to his chicken. The chicken gained weight with an efficiency of 0.84. Calculate the weight gained by the chicken.
4 Magnification
Quest
ion 4.1 Calculating the magnifying power of lenses Answer
1 Calculate the magnification of the virtual image produced by the following combinations of lenses:
a objective ×10 and eyepiece ×12
b objective ×40 and eyepiece ×15
a
b
Quest
ion 4.2 Calculating the magnification of images Answer
2 Calculate the magnification factor of a mitochondrion that is 1.5 µm long. You will need to refer to the image on the sheet.
Quest
ion 4.3 Calculating real dimension
3 Use the magnification factor to determine the actual size of a bacterial cell.